The only place I would leave the Big XII for is the Big X. The revenue sharing would be WAY better, we'd be playing in an easier conference, and we would have our own network.
I also wouldn't consider leaving the Big XII for the Big # "giving up." Then again, I doubt it would ever happen, as the Big # would first have to get serious about adding the 12th member and then Notre Dame, Missouri, Nebraska, Pittsburgh, Rutgers, and Syracuse would all have to turn down the offer to join first.